jQuery.base64 = (function($) {

	var _PADCHAR = "=", _ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", _VERSION = "1.1";//Mr. Ruan fix to 1.1 to support asian char(utf8)

	function _getbyte64(s, i) {
		// This is oddly fast, except on Chrome/V8.
		// Minimal or no improvement in performance by using a
		// object with properties mapping chars to value (eg. 'A': 0)

		var idx = _ALPHA.indexOf(s.charAt(i));

		if (idx === -1) {
			throw "Cannot decode base64";
		}

		return idx;
	}

	function _decode_chars(y, x) {
		while (y.length > 0) {
			var ch = y[0];
			if (ch < 0x80) {
				y.shift();
				x.push(String.fromCharCode(ch));
			} else if ((ch & 0x80) == 0xc0) {
				if (y.length < 2)
					break;
				ch = y.shift();
				var ch1 = y.shift();
				x.push(String.fromCharCode(((ch & 0x1f) << 6) + (ch1 & 0x3f)));
			} else {
				if (y.length < 3)
					break;
				ch = y.shift();
				var ch1 = y.shift();
				var ch2 = y.shift();
				x.push(String.fromCharCode(((ch & 0x0f) << 12)
						+ ((ch1 & 0x3f) << 6) + (ch2 & 0x3f)));
			}
		}
	}

	function _decode(s) {
		var pads = 0, i, b10, imax = s.length, x = [], y = [];

		s = String(s);

		if (imax === 0) {
			return s;
		}

		if (imax % 4 !== 0) {
			throw "Cannot decode base64";
		}

		if (s.charAt(imax - 1) === _PADCHAR) {
			pads = 1;

			if (s.charAt(imax - 2) === _PADCHAR) {
				pads = 2;
			}

			// either way, we want to ignore this last block
			imax -= 4;
		}

		for (i = 0; i < imax; i += 4) {
			var ch1 = _getbyte64(s, i);
			var ch2 = _getbyte64(s, i + 1);
			var ch3 = _getbyte64(s, i + 2);
			var ch4 = _getbyte64(s, i + 3);

			b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12)
					| (_getbyte64(s, i + 2) << 6) | _getbyte64(s, i + 3);
			y.push(b10 >> 16);
			y.push((b10 >> 8) & 0xff);
			y.push(b10 & 0xff);
			_decode_chars(y, x);
		}
		switch (pads) {
		case 1:
			b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12)
					| (_getbyte64(s, i + 2) << 6);
			y.push(b10 >> 16);
			y.push((b10 >> 8) & 0xff);
			break;

		case 2:
			b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12);
			y.push(b10 >> 16);
			break;
		}
		_decode_chars(y, x);
		if (y.length > 0)
			throw "Cannot decode base64";
		return x.join("");
	}

	function _get_chars(ch, y) {
		if (ch < 0x80)
			y.push(ch);
		else if (ch < 0x800) {
			y.push(0xc0 + ((ch >> 6) & 0x1f));
			y.push(0x80 + (ch & 0x3f));
		} else {
			y.push(0xe0 + ((ch >> 12) & 0xf));
			y.push(0x80 + ((ch >> 6) & 0x3f));
			y.push(0x80 + (ch & 0x3f));
		}
	}

	function _encode(s) {
		if (arguments.length !== 1) {
			throw "SyntaxError: exactly one argument required";
		}

		s = String(s);
		if (s.length === 0) {
			return s;
		}

		//s = _encode_utf8(s);
		var i, b10, y = [], x = [], len = s.length;
		i = 0;
		while (i < len) {
			_get_chars(s.charCodeAt(i), y);
			while (y.length >= 3) {
				var ch1 = y.shift();
				var ch2 = y.shift();
				var ch3 = y.shift();
				b10 = (ch1 << 16) | (ch2 << 8) | ch3;
				x.push(_ALPHA.charAt(b10 >> 18));
				x.push(_ALPHA.charAt((b10 >> 12) & 0x3F));
				x.push(_ALPHA.charAt((b10 >> 6) & 0x3f));
				x.push(_ALPHA.charAt(b10 & 0x3f));
			}
			i++;
		}

		switch (y.length) {
		case 1:
			var ch = y.shift();
			b10 = ch << 16;
			x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F)
					+ _PADCHAR + _PADCHAR);
			break;

		case 2:
			var ch1 = y.shift();
			var ch2 = y.shift();
			b10 = (ch1 << 16) | (ch2 << 8);
			x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F)
					+ _ALPHA.charAt((b10 >> 6) & 0x3f) + _PADCHAR);
			break;
		}

		return x.join("");
	}

	return {
		decode : _decode,
		encode : _encode,
		VERSION : _VERSION
	};

}(jQuery));